1. Field of the Invention
The present invention relates to amino-formaldehyde resins, processes for manufacturing amino-formaldehyde resins, and applications thereof. The present invention particularly relates to urea-formaldehyde resins, melamine formaldehyde resins, and melamine-urea-formaldehyde resins, processes for manufacturing the same, and applications thereof.
2. Background of the Art
Formaldehyde is one of the most common chemicals used in industry. International production was over 46 billion pounds in 2004, according to the International Agency for Research on Cancer (IARC). It is well known as a preservative in medical laboratories, as an embalming fluid, and as a sterilizer. Formaldehyde's primary use is in the production of resins and as a chemical intermediate. Urea-formaldehyde and phenol formaldehyde resins are used in foam insulations, as adhesives in the production of particleboard and plywood, and in the treating of textiles.
In the wood products industry, there is a growing concern over formaldehyde emissions. As a result many different reduced formaldehyde or non-formaldehyde adhesive systems have emerged. These systems generally include: (i) changing the reaction mixture of the formaldehyde adhesive resin; (ii) adding formaldehyde-scavenging materials directly to the formaldehyde resin; (iii) separately adding formaldehyde-scavenging materials to the wood furnish; (iv) treating panels after manufacture either with a formaldehyde scavenger or by applying coatings or laminates; and (v) changing to an entirely different adhesive system.
Unfortunately, in some of these systems, the bond strength and physical properties of composite boards are detrimentally affected. For example, lowering the mole ratio of urea-formaldehyde (UF) resins typically increases cure time and reduces the bond strength and physical properties of composite boards due to a reduction in the extent of cross-linking during curing.
Therefore, it would be desirable in the art of making amino-formaldehyde resins and articles of manufacture with reduced formaldehyde emissions without the detrimental effects on physical properties.